One example of a display device that displays a video image while modulating an amount of light emitted from a light source based on a video signal is a liquid crystal display device. In recent years, a display of mobile phones and computers, or a liquid crystal display device applied to televisions, include a liquid crystal display panel and a light source unit. The light source unit is classified into a backlight type or a sidelight type, however in whichever case, the light source unit is capable of uniformly emitting light to the liquid crystal display panel.
A backlighting control technique that periodically turns the backlight on and off is known as a technique to reduce the amount of electricity consumption of such a liquid crystal display device. Patent Literature 1 shown below focuses on a problem in the conventional backlighting control technique, in which flickering occurs caused by interaction of a frequency at a time when updating of data is carried out in a liquid crystal display device with a frequency at which the backlighting is provided. In order to solve this problem, Patent Literature 1 discloses a method and a circuit that generate a pulse width modulating signal for turning the light source on and off so as to synchronize with each frame of display data provided to a liquid crystal display device.